Biomes in Unexpected Places

A new kind of habitat was found in 1984 with the discovery of organisms, including tube worms over 2 m long that may be centuries old, that thrive on petroleum seepage on relatively cold ocean floors. These colonies, which may contain hundreds of different species, are especially abundant on the seabed of the Gulf of Mexico, where Spanish accounts from the 1500s noted oil slicks from natural petroleum leakage. 

Organisms and the ecosystems in which they exist are subject to a number of threats that can result in loss of populations and even total destruction of the system. Natural threats include drought, flooding, fire, landslide, and volcanic eruption. Humans threaten life systems with cultivation, deforestation, mining, and severe pollution. The ability of a community of organisms to resist alteration and damage from such threats, sometimes called inertia, depends on several factors and provides important lessons for the survival of the human community in the face of environmental threats. 

One of the basic factors involved in providing resistance of a community to damage is its overall rate of photosynthesis, its productivity (see Section 12.3). important factor is diversity of species so that if one species is destroyed or seriously depleted, another species may take its place. Constancy of numbers of various organisms is desirable wide variations in populations can be very disruptive to a biological community. Finally, resilience is the ability of populations to recover from large losses. 

The ability of a biological system to maintain high levels of the desirable factors of productivity, diversity, constancy, and resilience is commonly determined by factors other than the organisms present. This is clearly true of productivity, which is a function of available moisture, suitable climate, and nutrient-rich soil. Since all organisms depend on the availability of good food sources, diversity, constancy, and resilience tend to follow high productivity. 

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